July 13, 2005
Organic farming produces same corn and soybean yields as conventional
farms, but consumes less energy and no pesticides, study finds
By Susan S. Lang
ITHACA, N.Y. -- Organic farming produces the same yields of corn and
soybeans as does conventional farming, but uses 30 percent less energy,
less water and no pesticides, a review of a 22-year farming trial study
David Pimentel, a Cornell University professor of ecology and
agriculture, concludes, "Organic farming offers real advantages for
such crops as corn and soybeans." Pimentel is the lead author of a
study that is published in the July issue of Bioscience (Vol. 55:7)
analyzing the environmental, energy and economic costs and benefits of
growing soybeans and corn organically versus conventionally. The study
is a review of the Rodale Institute Farming Systems Trial, the longest
running comparison of organic vs. conventional farming in the United
"Organic farming approaches for these crops not only use an average of
30 percent less fossil energy but also conserve more water in the soil,
induce less erosion, maintain soil quality and conserve more biological
resources than conventional farming does," Pimentel added.
The study compared a conventional farm that used recommended fertilizer
and pesticide applications with an organic animal-based farm (where
manure was applied) and an organic legume-based farm (that used a
three-year rotation of hairy vetch/corn and rye/soybeans and wheat).
The two organic systems received no chemical fertilizers or pesticides.
Inter-institutional collaboration included Rodale Institute agronomists
Paul Hepperly and Rita Seidel, U.S. Department of Agriculture's
Agricultural Research Service research microbiologist David Douds Jr.
and University of Maryland agricultural economist James Hanson. The
research compared soil fungi activity, crop yields, energy efficiency,
costs, organic matter changes over time, nitrogen accumulation and
nitrate leaching across organic and conventional agricultural systems.
"First and foremost, we found that corn and soybean yields were the
same across the three systems," said Pimentel, who noted that although
organic corn yields were about one-third lower during the first four
years of the study, over time the organic systems produced higher
yields, especially under drought conditions. The reason was that wind
and water erosion degraded the soil on the conventional farm while the
soil on the organic farms steadily improved in organic matter,
moisture, microbial activity and other soil quality indicators.
The fact that organic agriculture systems also absorb and retain
significant amounts of carbon in the soil has implications for global
warming, Pimentel said, pointing out that soil carbon in the organic
systems increased by 15 to 28 percent, the equivalent of taking about
3,500 pounds of carbon dioxide per hectare out of the air.
Among the study's other findings:
# In the drought years, 1988 to 1998, corn yields in the legume-based
system were 22 percent higher than yields in the conventional system.
# The soil nitrogen levels in the organic farming systems increased 8
to 15 percent. Nitrate leaching was about equivalent in the organic and
conventional farming systems.
# Organic farming reduced local and regional groundwater pollution by
not applying agricultural chemicals.
Pimentel noted that although cash crops cannot be grown as frequently
over time on organic farms because of the dependence on cultural
practices to supply nutrients and control pests and because labor costs
average about 15 percent higher in organic farming systems, the higher
prices that organic foods command in the marketplace still make the net
economic return per acre either equal to or higher than that of
conventionally produced crops.
Organic farming can compete effectively in growing corn, soybeans,
wheat, barley and other grains, Pimentel said, but it might not be as
favorable for growing such crops as grapes, apples, cherries and
potatoes, which have greater pest problems.
The study was funded by the Rodale Institute and included a review of
current literature on organic and conventional agriculture comparisons.
According to Pimentel, dozens of scientific papers reporting on
research from the Rodale Institute Farming Systems Trial have been
published in prestigious refereed journals over the past 20 years.